To acknowledge that the church often needs to fight for truth is not to suggest that the gospel—our one message to a lost world—is somehow a declaration of war. It most certainly is not; it is a manifesto of peace and a plea for reconciliation with God (2 Corinthains 5:18-20). Conversely, those who are not reconciled to God are at war with Him all the time, and the gospel is a message about the only way to end that war. So ironically, the war to uphold the truth is the only hope of peace for the enemies of God.
I do agree that usually it is far better to be gentle than to be harsh. Peacefulness is a blessed quality (Matthew 5:9); pugnaciousness is a disqualifying character flaw (Titus 1:7). Patience is indeed a sweet virture, even in the face of unbelief and persecution (Luke 21:19). We always ought to listen sufficiently before we react (Proverbs 18:13). A kind word can usually do far more good than a curt reaction, because "a soft answer turns away wrath, but a harsh word stirs up anger" (Proverbs 15:1)—and any person who delights to stir up strife is a fool (Proverbs 15:8).
Furthermore, the fruit of the Spirit is a catalog of antitheses to a bellicose, aggressive, warlike attitude: "love, joy, peace, longsuffering, kindness, goodness, faithfulness, gentleness, self-control" (Galatians 5:22-23). So our first inclination when we encounter someone in error ought to be the very same kind of tender meekness prescribed for anyone in any kind of sin in Galatians 6:1: "If a man is overtaken in any trespass, you who are spiritual restore such a one in a spirit of gentleness, considering yourself lest you also be tempted." It is the duty of every Christian "to speak evil of no one, to be peaceable, gentle, showing all humility to all men. For we oursleves were also once foolish, disobedient, deceived, serving various lusts and pleasures, living in malice and envy, hateful and hating one another" (Titus 3:2-3). And that attitude is a particular duty for those in spiritual leadership. Brawlers aren't qualified to serve as elders in the church (1 Timothy 3:3). Because " a servant of the Lord must not quarrell but be gentle to all, able to teach, patient, in humility correcting those who are in opposition, if God perhaps will grant them repentance, so that they may know the truth" (2 Timothy 2:24-25).
All those principles should indeed dominate our dealings with others and our handling of disagreements. And if those were the only verses in Scripture that told us how to deal with error, we might be justified in thinking those principles are absolute, inviolable, and applicable to every kind of opposition or unbelief we encounter.
But that's not the case. We are instructed to contend earnestly for the faith (Jude 3). Immediately after the apostle urged Timothy to "pursue righteousness, godliness, faith, love, patience, gentleness" (1 Timothy 6:11), he exhorted him to "fight the good fight of faith" (v. 12), and to guard what had been committed to his trust (1 Timothy 6:20).
The love promoted bythe New Testament is not a free-styled, all-embracing, blind acceptance of every wind of doctrine for the sake of conversation. It is, in fact, just the opposite. Biblical love always goes hand in hand with truth. That's why false doctrines and those who teach them are condemned in no uncertain terms.
Jesus said: Beware of the false prophets, who come to you in sheep’s clothing, but inwardly are ravenous wolves.
Paul said: If any man is preaching to you a gospel contrary to what you received, he is to be accursed!
Peter said: It has happened to them [false teachers] according to the true proverb, “A DOG RETURNS TO ITS OWN VOMIT,” and, “A sow, after washing, returns to wallowing in the mire.”
John said: If anyone comes to you and does not bring this teaching, do not receive him into your house, and do not give him a greeting; for the one who gives him a greeting participates in his evil deeds.
Jude said: But these men revile the things which they do not understand; and the things which they know by instinct, like unreasoning animals, by these things they are destroyed.
Adapted from John's new book, The Jesus You Can't Ignore.